The influence of pore size and oxidizing agent on the energetic properties of porous silicon

Abstract

The explosive properties of porous silicon (pSi) provide an alternative to existing carbon-based explosives. Here, an investigation into these explosive properties is conducted, by introducing an oxidiser onto freshly etched pSi films with varying pore sizes as determined by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Explosions are triggered via the application of an electric spark. Light output and spectral data are collected to characterize the explosion. Measurements of light output indicate that sodium perchlorate produces the most brilliant explosions, however spectral data indicate that aluminium and gadolinium nitrates produce hotter explosions. The energy output is measured by means of Differential Scanning Calorimetry (DSC), indicating that almost 9 kJ/g is released, double that released by the detonation of TNT. The energetic material cyclo-1,3,5-trimethylene-2,4,6-trinitramine (RDX) is added to investigate a method of improving explosive performance of pSi, with disappointing results.

A Decade of Porous Silicon as Nano‐Explosive Material

“…The sharp peak at 589 nm is due to sodium impurities from atmospheric contaminants. Similar wideband results were reported with the maximum emission intensity in the range of 680 nm for sodium perchlorate and aluminum nitrate [17]. A more detailed spectrum of calcium perchlorate emission also exhibited a wide band emission, but with a number of sharp plasma lines [4,23].…”

“…The influence of pore size and oxidizing agent on the energetic properties of porous silicon were determined experimentally using differential scanning calorimetry (DSC) techniques [17]. The highest energy output was measured for the oxidizer sodium perchlorate, almost 9 kJ g À1 , which compared well with the theoretical predicted energy yield of 10.35 kJ g À1 .…”

“…Aluminum nitrate as an oxidizer was implemented and a 0.2m solution in ethanol was used for pore impregnation [17]. The results indicated that aluminum nitrate was not as effective an explosive material as either gadolinium nitrate or sodium perchlorate.…”

“…From Figure 7 it can be seen that a pore size in the region of 3 to 4 nm was optimal for devices using the oxidizers shown in the Figure [37]. Another study concluded that a pore size of 11.8 nm was optimal for the oxidizer aluminum nitrate [17]. There is evidently an optimum pore size suited to specific explosive systems.…”

Characterization of Porous Silicon by Calorimetry

“…Salonen (Salonen et al 1999b) Reactivity in solution IMC Salonen (Salonen et al 1997a(Salonen et al , 2001), Riikonen (Riikonen et al 2012 Plummer (Plummer et al 2008), Becker (Becker et al 2010) fraction of the drug in the sample can be calculated relatively accurate (Salonen et al 2005a). This makes the combination of TG and DSC a fast and simple method to estimate the amount and physical state of the drug loaded.…”